1. Field of the Invention
The invention relates to apparatus, e.g., a camera back, for locating a film cassette in position for the sequential exposure of a plurality of premounted transparency frames of the instant type contained therein.
2. Description of the Prior Art
Apparatus for locating a film cassette in position for the sequential exposure of a plurality of premounted transparency frames of the instant or self-processing type contained therein are generally well known. Representative examples of such apparatus are shown and described in U.S. Pat. Nos. 4,172,647, 4,132,471, 4,114,166, 3,525,293, 3,369,470, and 3,225,671.
The apparatus disclosed in the '647 patent takes the form of a camera back which may be readily attached to a conventional camera of the 35 mm type. The camera back includes a chamber for locating a film cassette containing a stack of premounted transparency frames of the instant type in position for their sequential exposure. After the film units have been processed and removed from the camera back, a strippable opaque back is removed therefrom in preparation for the viewing of the transparency frames.
In the '471 patent, the apparatus takes the form of a self-developing type camera in which premounted "instant slides" are exposed, directed between a pair of processing rollers which rupture a container of processing liquid and spread its contents between specific layers of the film unit, and the film unit is then deposited in a lightight chamber until the latent image has been developed. Thereafter, the processed film unit may be removed from the chamber and an opaque backing sheet stripped therefrom prior to being placed in a projector.
In the '166 patent the apparatus also takes the form of a self-developing type camera wherein individual premounted transparency frames are moved from a film cassette into an exposure chamber wherein the frame is photographically exposed. After exposure, the frame is moved between a pair of processing rollers and then into a lighttight storage cassette where it remains until the latent image has been developed. Thereafter, the frame may be removed from the storage cassette and placed in a projector for viewing.
The apparatus of the '293 patent also takes the form of a camera of the self-developing type wherein individual premounted transparency frames are sequentially moved from a cassette into a exposure chamber. After the frame has been exposed, it is moved into a developing chamber where a roller ruptures a container of processing liquid and spreads its contents between layers of the film to initiate the formation of a visible image within the film unit. Thereafter, the processed film unit is removed from the camera, its garbage, e.g., pod, strip sheet and absorbent material, is stripped from the frame so that it is ready for viewing.
Finally, the '470 and '671 patents show self-developing type cameras for use with film assemblages of the type having a film cassette which houses a stack of premounted transparency frames of the instant type. The frames are adapted to be individually exposed, removed from their cassette and processed by spreading a processing liquid in a layer between elements of the transparency frame, and then removed from the camera. However, before they may be viewed, opaque backing sheets must be removed from the frames.
While the foregoing apparatus may perform their intended functions they still have deficiencies which detract from their usefulness. For example, they are not capable of storing one or more exposed film frames for later processing at a more compatible temperature while still permitting the continued exposure of the remaining film frames in the cassette. Further, the structure for supporting the film cassettes in position for the exposure of their respective film frames cannot be attached to a separate film processor for processing of the exposed film frames without exposing one of the film frames to the ambient light. Further, an operator of one of the above described apparatus is presented with a processed film frame which is either not in condition to be placed in a projector until various elements have been stripped or otherwise removed therefrom, or the processed frame is of the type wherein the image-recording and image-receiving layers are permanently laminated together thereby decreasing its transmittance ratio.